I've thought about this question quite a lot.
I sometimes think that marriage is a sort of practice ground for the sort of love that we ought to have for every human being that we meet. But having that sort of love, compassion, trust, and devotion for everyone...well, that's pretty darn impossible, at least for us earthly human beings.
So we pick one person to devote ourselves to, one person to practice that all-consuming, all-encompassing love that sees another through sickness and health, life and death.
I suspect that all of those memories of building that love together, all of that joy that you found in each other, and all of that happiness that you had in learning how to love one another...that'll all be there when you get to heaven. It's just that, instead of being focused inward on just the two of you, all of that joy and love will also be turned outward so that you can share that love with everyone. You know those couples who alienate the rest of their friends and just make goo-goo eyes at one another and sort of create this wall around just the two of them? That's not the sort of love that's raised up again in heaven. But how about those couples who just seem to breath love and life into everyone they meet; they're the glue that holds large friend groups together, that welcomes strangers into their homes, that make others feel included and loved without ever needing to go around flaunting their married status----that's the sort of marriage that's heaven bound, I think.
In the bible story, I think Jesus was shooting down the question of ownership and belonging (especially considering the time period he spoke in. The Saduccees basically wanted to know who got to lay claim to the woman. They never brought love into the equation). In a heavenly community, people simply aren't worried about who belongs to who....I think he means that we'll all be so caught up in the joy of that new life that whether some woman belongs to this man or that man won't be an issue.
I don't know if any of that makes sense but, basically: it's not like heaven would erase the fact that you spent a lifetime building a love between you and your spouse. It's just that "who belongs to who" won't be an issue any longer.
I married my soulmate.
They were a wonderful person that is completely irreplaceable. I'm learning that I have to create a new life now. To me that means I will still find another wonderful woman and love them, not as a replacement, but as someone completely different. I think that I will probably end up with a widow as they will most likely understand and know what I've been through.